Some oil and gas formations can be made economically feasible to drill to recover hydrocarbons by hydraulic fracturing (“Fracking”). Fracking involves the injection, at very high pressure, of a fluid (typically mainly water) with a proppant (typically silica sand). Fracking has been a key technological advancement that has allowed increased production of oil and gas from low porosity formations such as shale, coal seam and generally tight zones.
After a well that has been fracked is completed, the well is tested and then put onto production. At this stage, some of the massive quantities of fracking fluid and proppant flow back to the surface along with hydrocarbons and formation water. The highly erosive nature of this initial production creates significant problems in production equipment downstream of the well.
These difficulties may be handled by placing sand separation, or desanding, equipment immediately downstream of the well. The desanding equipment may be kept in place until the sand flow-back reduces to an acceptable level. This can take several months.
There is a need for improved desanding equipment, especially equipment that can be operated unattended for significant periods of time. There is a particular need for such equipment that can be operated in a way that avoids discharge into the environment of hydrocarbons or sand that is potentially contaminated with hydrocarbons at the location of a well.